The present invention relates to a fuse of a semiconductor device and a method for forming using the same, and more specifically, to a fuse of a semiconductor device and a method for forming using the same that may prevent damage of the lower layer from misalignment due to lack of a blowing margin.
A semiconductor device such as a memory device and a memory merged logic (MML) includes a plurality of memory cells for storing data. If even one memory cell in a memory array of a semiconductor device has a defect, the whole device is not able to serve as a memory since the whole device becomes defective. However, if a whole memory device is discarded when it is determined to contain a defective memory cell, it significantly lowers a manufacturing yield.
In order to improve a manufacturing yield of a semiconductor device including a memory device or a memory, a repair method is required. The repair method in the semiconductor device is performed by replacing a defective memory cell with a redundancy memory cell. In order to replace a defective memory cell with a redundancy memory cell, a fuse is used. Specifically, a semiconductor device is configured to include a plurality of fuses, and these fuses can be cut using a laser. A test is performed to determine whether a defective memory cell exists in a given semiconductor device, and then the fuses are selectively cut depending on the test result.
In the repair method using a redundancy cell, each cell array comprises a redundancy word line and a redundancy bit line, and when a defect is found in a specific cell, the normal word line or the normal bit line is substituted with the redundancy word line or the redundancy bit line. In a memory device, when a defective cell is identified through a test, circuit lines are reconfigured to substitute an existing address corresponding to the defective cell with a new address corresponding to a redundancy cell. As a result, when an address signal corresponding to the defective cell is inputted, the substituted redundancy cell corresponding to the defective cell is activated.
Of the above-described repair methods, a widely used method is to blow a fuse with a laser beam, thereby performing cell substitution. For this operation, a general memory device has a fuse unit configured to substitute an existing address path with a new address path by blowing the fuse of a defective cell using a laser. A wire designed to be disconnected by laser irradiation is referred to as a metal fuse, and the disconnection site and its surrounding region are referred to as a fuse box.